Dispelling the Myths of HD Video Conferencing – Part 4 of 7

Myth 4: HD video equates to long latency and low frame rates

Fact: High definition video latency is less than the latency experienced with a cell phone.

A full high definition video communications system (such as LifeSize® Room™ 220) is powerful enough to deliver 30 to 60 frames per second of up to 1080p for the highest quality and low latency. Gone are the days of CIF-based video at 352×288 at somewhere between 20-30 frames per second.

A bit about LifeSize’s approach to frame rate consistency:

LifeSize supports bitrate downspeeding in all of its video endpoints.

In the event that LifeSize does need to reduce its bitrate to support the video conference, LifeSize’s approach to downspeeding always maintains the frame rate at 30 or 60 fps (depends upon selection of 720p60 or 1080p30 mode). This approach contradicts methods taken by other video vendors, whose products will try to maintain the resolution, while reducing the frame rate. This method of downspeeding can lead to a stop-motion visual experience, where the HD resolution is moving at 10 or less frames per second. At LifeSize, we believe that frame rate should never be compromised.

For example, in a scenario where an HD video call at 1280×720 at 30fps uses 768Kbps of bandwidth, the available bandwidth could then decrease to 512 Kbps due to network congestion. In response, the LifeSize system will decrease the resolution to only 1024×576 while maintaining 30 fps. Though 1024×576 is a lower resolution, the image will still be visible to users, and because the frame rate did not change, the integrity of the video call remains consistent. In a similar situation with Competitor A, the initial video call using 768Kbps bandwidth is at 1024×576 resolution (below HD video quality) at 30 fps. If the bandwidth decreases to 512Kbps due to network congestion, Competitor A’s system will decrease the resolution to only 768×448 (below DVD video quality) and maintain 30 fps.

Stop-motion animation of a Lego car. Cute now, not so cute during an important video call. (Photo Courtesy of Wikipedia)

Many of us have experienced the aforementioned “stop-motion visual experience” in video conferencing scenarios. LifeSize understands how inefficient this type of communication can be. Through our technology, LifeSize has taken steps to eliminate latency on high definition video calls by reducing resolution, rather than frame rate, to accommodate a drop in bandwidth.

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